Continuous ice-cream freezer and method of making ice cream



Sept. 8, 1953 w. L. MURPHY 2,651,186 CONTINUOUS ICE-CREAM FREEZER AND METHOD OF MAKING ICE CREAM Filed Jan. 17, 1951 2 Sheets-Sheet l INVENTOR. M44 752 Z Moe/21 E LSM HTTOPA/E) Sept. 8,

Filed Jan. 17, 1951 W. L. MURPHY CONTINUOUS ICE-CREAM FREEZER AND METHOD OF MAKING ICE CREAM 2 Sh t. sh 2 as seat 76 l8 76 44. 3 62 x n i .2' 56 65 x 6 7 f 54 J A 4 l I 44- In "I 46 52 5 44 f O g 58 INVENTOR.

94 30 lkkwh 54 HTroEA/EY Patented Sept. 8, 1 953 GON'IINUOUS'ICE- METHOD :OF M Walter L. Murph CREAM FREEZE-R AKING ICE :GREAM Kansas .,Qi ty, M0,, assignor .jt

De-Raef Corporation, inspiration o Mi so ansas flitmfM a co Application-January 517, 1951i, .Serial -No. 30 .1378

10 Claims.

My invention relates to atcontinuousiice-cream f zer :and at :method of makin ice cream and more particularly to .an improved contin ous ice cream freezer of simplified const uction and an improved :method of --rnaking ice :cream in which therefrigeration load is r duced- 'Ice cream freezers of the prior a1- t employ mechanical refrigeration and {are complicated and expensive pieces ,of equipment. In the process ,of freezing, air is incorporated with the ice cream mix :to ohtainadesilied overrun. The inclusion of sma lparticles or air mak s w in ed ice cream mix havin such particles of air incorporated therein ditficult to :freeze. Each particle of air acts a .a small dead air space Y and hence insulation. .In the freezing process it is necessary to chill the .airito freezing temperature. Asaresult of the physical make-up of a whippedice cream @mix :a large refrigeration capacity .is necessary. In the prior art methods the air becomes chilled by the enclosing walls .of the .mix constituents.

Dne obje t of my invention is to provide a continuous ice cream freezerof low cost in which no mechanical refrigeration is employed.

Another object of my invention is to provides continuous ice cream freezer in which bottled compressed (inert gas such as air or nitrogen is expanded to provide the necessary refrigeration byiheat exchange and to precool the ice .cream mix by incorporatin he chilled expanded ga with the ice cream mix as the gas used in..pb.- etainin ver un. 1

.Another ohject of myinvention is to provide ta continuous ice am freezer whi h is simple t toner-ate.

Another object ofmyxinvent on is to pr v d a method of continuou ly f ezin ice c m i -.which-the refrigeration load .isreduced by incoriporating a chilled gas the ice cream mix to obtain zoverrun 1Other and Jfurther objects of my invention will appear from the following description.

in generahmy invention ontemplates the p oyision of a refrigerat on Jacket about a tube :through which the ice cream to be frozen passes. Bottle air or nitrogen is expanded into the jacket :to provide a refri erating medium which will freeze the -,icecream ;mix within the tube about which the Jacket is disposed. The expanded In the accompanying drawings which form chilledairds introduced into the ice cream mix more emeientluseof the re- A v p lcasinggfl .is'ip orided with en er qvsatit and wh ch are. to the read in conjunc ion therewithand in h ch showing theaconstructioniof the whipping .gnozzle. :More particularly referring ,now to th ws, t i e cr a mix wh ch may have an suitable composi ion 15 5 130 16? in a rat iiom 0 wh ch it is pumped through pipe 12 by means of a pump 14 -.thro a .hom' enizc k fi, Ethcnce ough ipe to a m in n zzle xi f m freezer. Aplurality of bottles 22 Z Landl 16 of ;a

gen or carbon dioxide, are connectedito ia gas 7 When I say inert gas Imean a gas.which will not deleteriously affect-an ice cream mix. Theibot tle 22 communicates'with ;theamanitold ,28 'by means of'a valve 30, the bottleidcome 39 municates vwith the; r 2 by :means of a waives ;is;provide;d with a vaIve housing I46? .=gas rm expanding come chi ed to a eryiow temperature T c il dnea in c a be b isiI contact with a tube .48 through which the ice py thecasingfiztand .thetube .43: .'I he cylindrioal a lower cover 56 secured thereto in any suitable The exterior of the freezer casing is provided with heat insulating lagging 58. The housings 46 of the expansion valves 42 are also provided with heat insulating material 60. The refrigerated chamber 40 is provided with a relief valve 62 to insure that pressure does not build up therein. The pressure within the chamber 40 is indicated by a pressure gauge 64. The chilled expanded gas leaves the 66 and passes into a whipping nozzle chamber 68, through which the pipe l8 containing the mix passes. The end of pipe I8 is provided with a plurality of spiral vanes 10 to give the mixemerging into a diverging passageway 12 a rotary motion. The front plate 14 of the mixing nozzle 28 is provided with a plurality of angularly directed openings 16, as can readily be seen by reference to Figure 3. These openings are directed to give the chilled expanded gas a rotary motion in the same direction as the rotary motion imparted to the mix by the vanes 10. The gas whirling with the mix will become thoroughly incorporated therewith, serving to whip the mix and produce overrun. The rate of overrun may be varied by controlling the volume of the gas by means of control knobs 44 with respect to the volume of the mix by controlling the speed of the pum i4. By incorporating the chilled expanded gas with the mix the mix becomes precooled. When the mix passes through the diverging passageway 12 a further expansion of the gas is permitted so that when the gas reaches the portion of the passageway 18 of greatest cross-sectional area the gas will be at substantially atmospheric pressure. At this point no further reduction in ture will be obtained by expansion the prechilled whipped mix enters the heat exchange tube 48. An auger 80 is mounted upon a shaft 82. The auger is positioned in the tube 48 and rotates to pass the mix through the heat exchange tube and to insure contact with the mix with the refrigerated surface of the tube 48. This further chills and finally freezes and ultimately hardens the mix in its passage through the tube 48 so that as it reaches the bottom of the tube it is an ice cream of the desired consistency and stiffness. A housing 84 extends through the passageway 12. The upper portion of shaft 82 is positioned in the housing 84 and is connected to the output gear of a reduction gear train housed within casing 86. An electric motor 88 furnishes power for rotating the shaft 82 and hence the auger 80. The frozen ice cream is adapted to pass from the tube 48 through a nozzle 90 of rectangular cross-sectional area. The nozzle is normally closed by a flap valve 92 secured to and carried by a shaft 94 passing through the nozzle 96. A spring 96 has one end thereof secured to the shaft 94 and the other end thereof secured to a member 98 which is rotatably carried by the shaft 94. A reciprocating pin I is carried by the coverhead G and is adapted to engage a plurality of openings I02 for-med in the member 98. By rotating the member 98 the tortional bias on the spring 96 can be adjusted and maintained by means of engaging the pin H in an opening 102. The spring biases the flap 92 to closed position so that the auger is adapted to feed the ice cream past the flap valve against the action of the spring. The speed of the motor 88 can be controlled to regulate the speed of passage of the ice cream mix being frozen through the freezing tube 48. The auger 80 scrapes ice cream from the inner walls of the freezing tube manner.

'48 and prevents portions of ice cream from atpressure against which chamber 40 through pipe teaching themselves to the walls and becoming frozen very hard and thus insulating the rest of the mix. The flap valve prevents the ice cream from flowing out of the tube by gravity and permits the ice cream to feed under the control of the auger. The bias on the spring controls the the auger feeds and furnishes a simple and convenient way of controlling the'stiffness and consistency of the finished ice cream. 7

It is believed that the operation of my apparatus and 'the' practice of my process will be clear from the foregoing description. In operation, the valves 44 areadjusted to start a flow of gas from the compressed gas bottles through the chilling chamber. This prechills and cools heat exchange tube 48, the whipping nozzle, the auger and all the parts. After these have been prechilled, the pump I4 is started and the mix is fed to the freezer. Overrun is determined by controlling the speed of the pump I4 with respect to the volume of gas passing into the whipping nozzle. If a greater overrun is desired, more gas and less mix is used. If less overrun is desired, more mix and less gas is used. The parts are designed so that overrun may be varied within reasonable limits. It is to be understood, of course, that a minimum amount of gas is required for the desired freezing action. Accordingly, only ice cream or other confections requiring the incorporation of gas to produce overrun can'be frozen in my freezer. Where a lower overrun is desired, it will be necessary to open bleeder valve 65 permitting a portion of the gas to pass to the atmosphere through pipe 61. The cracking of the bleeder valve insures the maintenanceof a sufficiently continuous expansion of ga to produce the desired temperature without at the same time requiring that all of the gas be incorporated in the mix. After the gas and the mix are properly proportioned by the adjustment of the speed of the pump M the opening of the expansion valves 42 and the proper adjustment of bleeder valve 65, the consistency of the finished ice cream is controlled in two ways. The first control is by the speed of the motor 88. If the ice cream is too stiff, the speed of the motor 88 is increased. If the ice cream is too soft, the speed of the motor 88 is reduced. Small changes in consistency of the finished ice cream can be controlled by the bias on the spring 95. If the ice cream is too stiif, the spring pressure may be reduced, reducing the back pressure against which the auger works. This ha the incidental effect of permitting the motor to run a little more rapidly since the load under which it works is reduced. If the ice cream is not stiff enough, the tortional bias of the spring 96 is increased. This increases the back pressure against which the auger 80 operates and has the incidental effect of reducing the motor speed.

During the operation the pressure gauge 64 is watched and when the pressure drops a new bottle of gasis out in by opening the proper gas manifold and bottle valves and the exhausted bottle is removed and replaced by a fresh bottle. Bottled gas is available in rural communitie and the large capital investment for expensive machinery can be avoided. The use of a tube in the auger precludes any corners or dead spaces so that when freezing is'changed from one flavor to another the marbling is avoided in successive runs. There is no danger that old hardened mix will contaminate-a subsequent run. In changfrom one flavor required the adjustments are made for proper continuous operation with a given mix.

A comparatively small equipment can produce rge volumes of ice cream in a simple, convenient and Having thus described my invention, what I claim is:

change fins on the into the jacket.

4. A continuous ice cream 1 in which the tube is provided with an outlet the atmosphere.

10. A method as in claim 7 including the step of creating a resistance to the passage of the ice cream mix through the chilling zone, and discharging the chilled ice cream mix from the chilling zone against the resistance.

WALTER L. MURPHY. 

